1. Field of the Invention
This invention relates to an element for biological reaction effectively employable for analysis based on dry chemistry, and to a process for the preparation of the same.
2. Description of Prior Arts
A great number of analytical systems for quantitative analysis of biochemically active components in a liquid sample employing the so called dry analytical element in the form of a sheet of layers is heretofore known (U.S. Pat. No. 3,050,373, etc.). These analytical processes generally utilizes an analytical element containing therein one or more components physically or chemically reactive upon contact to a component to be analyzed and contained in a liquid sample, namely, analyte, and comprises steps of: causing reaction between the reactive component(s) and the analyte introduced into the element within the biological reaction layer provided in the analytical element; and measuring the amount of the reaction product or unreacted component by a photometric or fluorometric measurement or by the use of radioisotope, whereby quantitatively determining the amount of analyte.
The analytical process using a dry analytical element (hereinafter, referred to as dry analytical process) has been widely utilized for various purposes, for example, immunoassay based on an antigen-antibody reaction, and analysis of enzyme or substrate based on an enzymatic reaction, between the analytical procedures employing the dry analytical element are relatively simple. However, poor analytical sensitivity is disadvantageous feature of the dry analytical process.
The present inventors have proposed an analytical element having a biological reaction layer in which a particulate solid carrying a biologically active substance fixed thereto is dispersed in a fibrous material: Japanese Patent Application No. 57(1982)-211382 (corresponding U.S. patent application was filed on Dec. 2, 1983, and EP application was filed on Dec. 2, 1983 under P 33 43 695.9). The reaction layer of this element functions to retain a liquid sample in an amount enough to perform the desired reaction. The present invention provides an improvement of the above-identified element particularly in the quantitative accuracy and handling of the element.
As for a biological reaction layer employing a fibrous material per se is disclosed in Japanese Patent Provisional Publication No. 57(1982)-196153, in which a biologically active substance such as enzyme is directly fixed to the fibers. However, such reaction layer shows difficulty in controlling the amount of an active substance to be fixed to the fibers.